Electrical systems in residential, commercial and industrial applications usually include a load center (also referred to as a panelboard) for receiving electrical power from a utility source. The power is connected to the load center via line bus bars and neutral bus bars. The electrical power is delivered from the load center to designated branch circuits through line and neutral conductors supplying one or more loads. Typically, various types of protective devices are mounted to the bus bars of the load center to protect the branch circuits from hazardous electrical conditions and reduce the risk of injury, damage or fires.
Standard circuit breakers are one type of protective device for protecting the branch circuits from certain hazardous electrical conditions. In particular, standard circuit breakers are designed to trip open and interrupt an electric circuit in response to detecting overloads and short circuits. Overload protection is provided by a thermal element which, when heated by the increased current, will cause the circuit breaker to trip and interrupt the power. This can occur when too many loads draw power from the same branch circuit at the same time, or when a single load draws more power than the branch circuit is designed to carry. Short circuit protection is provided by an electromagnetic element that trips when sensing high current flow.
One problem associated with some current load centers is that they include a bus bar assembly that fails to accommodate different sized circuit breakers. For example, this type of bus bar assembly will only accept one-inch circuit breakers or only half-inch circuit breakers, but not both. This type of bus bar assembly is inflexible and undesirable for numerous electrical applications.
Although some current bus bar assemblies try to address the above stated problem, this type of bus bar assemblies can be unreliable and can provide poor quality. For example, one bus bar assembly includes separate pairs of half-inch breaker stabs at multiple locations along a bus bar by either brazing or staking the half-inch breaker stabs to corresponding one-inch breaker stabs. This type of connection, either using a braze or a mechanical stake, inherently may introduce a problem-prone design that increases the opportunity for faulty connections (e.g., poor joining technique or material). Furthermore, this type of connection may fail over time due to stresses caused by normal use of circuit breakers (e.g., tripping the circuit breaker, replacing the circuit breaker, etc.). Additionally, the use of brazing and/or mechanical stakes can increase manufacturing costs and time.
What is needed, therefore, is a double bus bar assembly that addresses the above-stated and other problems.